Vocabulary in English, it's difficult to spell some words and vocabulary are largely semi formal language, which is different from the language used in the spoken idioms.
Some words in the English vocabulary is difficult spell. And vocabulary is mostly used semi-formal language, which is different from the language used in the expression of speech.
Terminology in English words is a tough spell. And vocabulary is mainly used for semi-formal language which is different from the language expressions used in speech.